Corneal preservation: past, present, and future.

In the past 15 years, techniques of corneal preservation have progressed from the storage of whole eyes in moist chambers for 24 hours at 4 degrees C to the preservation of isolated corneas for 1 week at 4 degrees C and for 1 month at 34 degrees C. Both of the latter techniques display a time-dependent deterioration of corneal tissue during storage. This deterioration has forced a reappraisal of corneal cryopreservation as a method for permanent corneal storage. Future advances will involve: decreasing this time-dependent deterioration by improving current techniques of 4 degrees C storage, and eliminating the deterioration by cryopreservation with a process called vitrification.